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Cycles for rational maps with good reduction outside a prescribed set

数论 2007-05-23 v3 代数几何

摘要

Let KK be a number field and SS a fixed finite set of places of KK containing all the archimedean ones. Let RSR_S be the ring of SS-integers of KK. In the present paper we study the cycles for rational maps of P1(K)\mathbb{P}_1(K) of degree 2\geq2 with good reduction outside SS. We say that two ordered nn-tuples (P0,P1,...,Pn1)(P_0,P_1,...,P_{n-1}) and (Q0,Q1,...,Qn1)(Q_0,Q_1,...,Q_{n-1}) of points of P1(K)\mathbb{P}_1(K) are equivalent if there exists an automorphism APGL2(RS)A\in{\rm PGL}_2(R_S) such that Pi=A(Qi)P_i=A(Q_i) for every index i{0,1,...,n1}i\in\{0,1,...,n-1\}. We prove that if we fix two points P0,P1P1(K)P_0,P_1\in\mathbb{P}_1(K), then the number of inequivalent cycles for rational maps of degree 2\geq2 with good reduction outside SS which admit P0,P1P_0,P_1 as consecutive points is finite and depends only on SS. We also prove that this result is in a sense best possible.

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引用

@article{arxiv.math/0504533,
  title  = {Cycles for rational maps with good reduction outside a prescribed set},
  author = {J. K. Canci},
  journal= {arXiv preprint arXiv:math/0504533},
  year   = {2007}
}

备注

30 pages, changed content